I get "software video rendering/accelerated video decoding" with the new Flash Player 11 beta 1 in Firefox 5.0 on openSUSE 11.4 64bit, with NVIDIA 280.04 driver, with "EnableLinuxHWVideoDecode=1" and "OverrideGPUValidation=true" in mms.cfg.

The CPU is 5 years old and almost always at 100% depending on the video, but playback is way smoother than before. 720p is OK, 1080p is a bit slow.

There's a perfectly good workaround for the lack of hardware-accelerated video rendering. Just right-click on the video and choose "Pop Out." That launches the video in a pop-up window, which is sized (by default) to the video's native size. You can drag the sides of that window to fill the whole screen, and the video will play at full frame rate.

Right-clicking on it selecting "Show Video Info" gives me "software video rendering, accelerated video decoding." Setting the resolution to 720p and playing it gives me a frame rate of 30fps with no dropped frames. If I use the "Full Screen" button at the bottom right, then the frame rate drops to 19fps (again, with no dropped frames). HOWEVER, if I instead pop it out and then drag the resulting pop-out window to almost fill the screen, then it plays at 30fps while filling as much of the screen as I want it to.

BTW really there are no big issues with videos up to 720p. At 1080 it gets interesting because that needs much more decoding muscle than 720p. 720p should work on any decent computer and decent internet connection without issues.

Enabling acceleration = after 1 day use I get browser crashes, then Xid errors when I start a game (+ artifacts like stains on walls and jumping dots, looks like broken memory on graphics card, with time I'd get better stuff). There goes my 2 months uptime :/